Internal combustion engine



y 26, 1932- J. PRENTICE 1,869,077

INTERNAL COMBUSTION ENGINE Filed Dec. 4, 1928 7 Z INVENTOR.

Lfdiizes frwzaq to, 'ATTORNEYd Patented July 26, 1932 PATENT OFFICE JAMES rmm'rrcn, or MIAMI, FLORIDA INTERNAL COMBUSTION ENGINE- Application filed December 4, 1928. Serial No. 323,611.

This invention relates to improvements in internal combustion engines and particularly to improvements in the formation of the combustion chamber of the cylinders of such engines. I

More particularly, the invention contemplates a combustion chamber for internal combustion engines wherein the surfaces of the walls of that chamber are so constltuted 19 that fouling by the accumulation of carbon deposits is reduced to a minimum. In this connection, those walls or surfaces of the engine structure adjacent the point of explosion of the gases in the charm er, are also so formed as to reduce the accumulation of carbon to a minimum. For instance, portlons of the head of the motor as Well as the surfaces of the valves may be protected.

It is a matter of common knowledge that 20 when, carbon deposits in the combustion chamber have accumulated to a certain extent, the explosions of. the engine take on character istics quite different from those created when the explosion chamber, the valves and the piston heads present substantially clean metallic surfaces. This is, the engine, when fouled by the accumulated carbon deposits g1ves forth certain characteristic sounds which, in common parlance, are called engine knocks 3, while amongst more concise and scientifically educated persons they are termed detonations. As a rule, an engine thus fouled heats quickly and has lubrication difficulties with incidental increased friction and consequent loss in efficiency. Eventually, unless and until the carbon is removed, the condition of the engine becomes such that the continued use thereof is inhibited. On the other hand, the

t removal of the carbon at frequent intervals 3 becomes an item of considerable expense and causes losses or delays in use which may be critical. Furthermore, an engine whose explosion chamber, valves and pistons have once been coated with highly heated carbon w1ll,

after each succeeding cleaning of the carbon, more uickly accumulate new coatings I he metallic surfaces of those parts, after havlng once been coated, are also changed in their physical and chemical characteristics much the same as iron which is heat treated 1n 9. crucible in the presence of carbon. Forinstance, such an engine will have pitted heads, pitted piston tops and Warped and pitted valves. In view of this, the present invention seeks to provide means for reducing this accumulation of carbon deposits to a minimum.

In carrying out the present invention it is desirable to provide the top surface of each piston, as well as the other surfaces mentioned, with a protected surface, so far as the accumulation of carbon is concerned and in this connection the invention proposes the provision of means for facilitating the dissipation of heat that would otherwise be retained at said surface. Specifically, it is proposed to place a cap of hard, smooth, noncatalytic, non-absorptive material, (which should also be of low corroding properties) on the top surface of the piston, the size of said cap being such as to provide clearance between the same and the cylinder wall. Because of this clearance, a filler preferably of magnesium or zirconium oxide in combination with flocculent graphite is interposed between the cap and piston thereby preventing the formation of air spaces and insuring a rapid dissipation of the heat units through the piston and walls of the cylinders.

With these and other objects in View, the present invention consists in certain novel details of construction and combinations and arrangements of parts, all as will hereinafter be more fully described and the novel features thereof particularly pointed out in the appended claims.

In the accompanying drawing,

Figure 1 is a sectional view through a portion of an engine block, illustrating more or less conventionally, a cylinder with its piston and one of the valves for controlling the passage of gases to or from said cylinder.

Fig. 2 is a similar view showing a modified form the invention may take.

It is a matter of common knowledge amongst chemists that carbon and iron and silicon, as well as combinations of those substances, in crystalline form are catalytic in action and as a result when hydrocarbon gases mixed with air come into contact therewith,

as shown in the accompanying hereinafter termed chrome iron.

the upper face of piston 13 has a cap 14 of the cost element would the? cause very quick and detonating unions an changes. To eliminate these crystahne formations, or at least to prevent their ad-' hesion to the surfaces of the losion chamber, said surfaces are prefera ly composed of a hard, smooth, non-catalytic and non.- absorptive material of low corroding properties. Such a surface is preferably formed illustrations by providing linersof a material wing v the above characteristics.

For instance, as shown in Fig. 1, the head 10 of the en 'ne block 11 is provided with a lining 12 w ich, for convenience will be ikewise the same material; each valve 15 is provided with a cap 16 and the surfaces of the en 0 block, which are exposed so as to accumu ate carbon, are lined as at 17. These linings andcaps are of the same material and may be secured in place in various ways. Separate lining members and cap; are preferred, as

entirely too high so far as the production of the structure from chrome iron is concerned.

As shown in Fig.3, the caps for the valves and pistons may provided withstuds or other securing. elements 18 and the caps placed in the molds preparatory to casting the valve or piston as the case may be. On the other hand, the valve or piston may be formed with a crimping groove 19, and the caps secured by crimping as illustrated in Fig. 2. This method of attachment may be used in installing the linings and caps on old, engines. It would only be necessary to cut the necessary ooves and attach the lining or member.

ig. 2 shows both the caps and the lining members attached by crimping.

In connection with the caps for the pistons, a rivet 20 of the same material as the cap may also be utilized at the center thereof. Th1s tends to prevent vibration or buckling of the cap although this feature is advantageously eliminated b the use of a filler 21 of good heat' con ucting qualities between the cap and piston. Due to the nature of the chrome iron it is important to provide clearance between the peripher of the piston cap and cylinder wall. There ore,

the cap is of smaller diameter than the piston proper and as a consequence there would be a tendency on the art of the cap to heat up tremendously shou (1 there be an air space between the same and the piston proper because such air space and the clearance at the. edge of the cap would greatly interfere with the transfer and dissipation of'the heat units. For this reason the filler 21 is referably composed of ma esium or zirconium oxide, combined wit flocculent graphite, either of which will facilitate the trans-- ferof heat units from the cap to the c linder block through the piston proper. e use advan the catalyst fails.

proposed in the present instance where a of flocculent graphite in this filler is very tageous. Being a lubricant, if used by itself, it would be moved around too much as the pressure is appliedto the protector sheeting. However, when combined with zirconium powders'migration of the graphite is prevented while, on the other hand, the zirconium owders will not be broken up b heat and temperature variations and wil not be powdered too fine by the impacts of the sheeting when pressure is being applied. While zirconium oxide, as a eneral proposition, is a good enough con uctor of heat for the temperatures involved, nevertheless, for the purpose of increasing the heat conducting properties of; the filler, as well as for the other reasons just stated, the flocculent gra bite is preferably used in combination wit the zirconium. The use of flocculent graphite is also facilitated by turning or pressing the edge of the sheeting in the grooves in the surfaces being covered, as this seals the graphite in. This is important because otherwise the graphite would quickly disappear. These materials retain the shape given them when pressed in place without the use of a binder.

It has heretofore been proposed to rovide explosion chambers of internal com ustion engines with catalytic linings. Suchlinings shell oil or dust away too quickly and are highly susceptible to attack by water fromthe cooling system. Such catalytic linings also become poisoned or are rendered. inactive by various impurities or foreign substances in the fuel, such as sulphur or tetraethyl lead which is now in common'use as an anti-knock ingredient ingasoline. From investigations conducted by ap licant it is believed that, as a rule, the ailure of such catalytic linings, which are really oxidizing agents that cause the carbon to'be burned when the engine is hot, can generally be traced to the penetration of sulphur fumes and oxygen t rough the linin with a resulting pitting or corroding o the iron or aluminum allo composin the engine block. In other wor s, the sur ace on which the catalyst is applied having been destroyed,

To overcome this, it is catal st is desired, to interpose a lining or cap between the catalyst and the body of metal on which it is used. For instance, as shown in Fig. 2 the caps and linings of the chrome iron are covered with a catalytic material 22. In this way, impurities inthe fuel can not gain-access to the metal formin the engine block, piston, etc., and do not a feet the material to which the catalyst is actually applied so as to destroy the catalyst. With a wall or piston surface of chrome iron, as roposed in the present instance, it is possib e to use the motor much longer due to the, fact that such material forms a surface that is hard, smooth, and non-corrosive or substantially so. It is also believed that v the use of such metal will also ermit of the design of engines wherein hig er pressures than those of today may be utilized, thereby securing increased efficiency. from the fuel used or the development of the same amount of power with a smaller consumption of fuel. Again the alloy proposed is ductile, whereby the lining or cap may be pressed into shape and portions thereof bent in applying the covering to the part to be protested. Castin is not resorted to in any instance. In tile preferred embodiment of the invention the material heretofore referred to as chrome iron, from which the piston and valve caps, etc., are formed, contains, in addition to the chrome and iron, a small percentage of copper. A small quantity of nickel may also be used where there is a necessity for deep drawing. The nickel also toughens the iron, resists acids, especial- 1y nitric acids, and, in addition, opposes grain growth.

Copper is used because it is the very essence of passivity in the chrome iron alloys.

"It also helps keep-the grain fine and aids in suppressing grain growth at high tempera tures. The preferred composition for the piston caps, etc., shouldv contain ap roximately 5 to 20% nickel (although as efore mentioned this ingredient may be dispensed with) and 1% of copper. The maximum quantity of copper is 2%. Wrought iron of not more than .3% carbon content is also preferably used, and there should not be over 14% chrome in the alloy. This limitation of the chrome content is proposed because chrome iron containing an excess of that percentage loses its self-hardening property. By maintaining the chrome content'at least as low as 14%, the caps or sheeting will be fully capable of allowing for expansion and con traction andwill not lose temper. therefore, always remain tight and well pressed in the grooves. It should also be added that this chrome iron alloy should be annealed before being bent, drawn or not exceeding 3/10% and the copper content is less than 2%.

2. In combination with combustion chamber surfaces of an internal combustion engine, a covering substantially proof a ainst carbon deposition, said covering ein formed of a smooth, hard, non-catalytic an non-absorptive material of low corroding properties, said material consisting of an alloy comprising iron with a carbon content not exceeding 3/10%; chrome and copper, the chrome content not exceeding 14% in the alloy and the copper not exceeding 2%.

3. In combination with combustion chamber surfaces of an internal combustion engine, a lining substantially proof against carbon deposition, said lining comprising a layer of a mixture of zirconium oxide and flocculent graphite and a surface covering of chrome wrought iron in sheet form attached and seamed at its extremities to said combustion chamber surfaces sealing the zirconium oxide and graphite mixture therebetween.

J AMES PRENTICE.

It will,

pressed into the grooves in the parts to be covered.

This application is a continuation in part of applicants co-pending application Serial No. 231,672, filed November 7, 1927.

What I claim is:

1. In combination with combustion chamber surfaces of an internal combustion engine, a covering substantially proof against carbon deposition, said covering being formed of a smooth, hard, non-catalytic and non-absorptive material of low corroding properties, said material consisting of an alloy comprising iron, chrome, copper and nickel in which the chrome content is less than 14%, the carboncontent of the iron 

